1. Field of the Invention
The present invention relates to a power transmission system for use in a vehicle including a power split device which performs power distribution among a flywheel for storing rotational energy as mechanical energy, an internal combustion engine and an electric rotating machine.
2. Description of Related Art
As such a power transmission system, there is the one in which a planetary gear device performs power distribution of the power between a transmission coupled to drive wheels and an internal combustion engine, the power of a flywheel, and the power of an electric rotating machine. For example, refer to International Patent Application Publication No. WO 2009/010819. According to this system, it is possible to store torque of the drive wheels in the flywheel or the electric rotating machine through the transmission.
However, the above conventional system has a problem in that it may occur that a vehicle-mounted battery cannot be charged properly by electric energy which the electric rotating machine generates by converting the rotational energy stored in the flywheel into electric energy while the vehicle runs, because the conversion by the electric rotating machine is affected by the rotational speed of the drive wheels.